Child-resistant closure and container packages are conventionally employed for prescription vials, vitamin bottles and a number of other applications. The present invention deals particularly with those types of child-resistant packages that involve application of axial pressure to the closure and simultaneous turning of the closure with respect to the container in order to remove the closure from the container. The present invention involves a number of features or aspects in a child-resistant closure, container or package, which may be implemented separately from or more preferably in combination with each other.
The present invention embodies a number of features or aspects that may be used separately from or, more preferably, in combination with each other. In accordance with a first aspect of the present invention, a child-resistant closure and container package includes a container having a finish with at least one external thread and pockets in the thread. A closure has a base wall, a peripheral skirt with at least one internal thread and lugs on the internal thread for receipt in the pockets, and a spring element on the base wall for engagement with the container finish to bias the closure away from the container finish and resiliently urge the lugs into the pockets. A liner preferably is urged by the spring element into engagement with the container finish. The liner may include a base with metal and plastic layers for induction-welded sealing engagement with the finish such that, upon removal of the closure, the metal and plastic layers remain secured to the finish and the liner base is removed with the closure. The metal and plastic layers may be removed by a user for access to the contents of the container, and the liner base continues to serve as a package seal during use of the package. The package may alternatively be supplied with a mono-layer liner, or without a liner.
In accordance with another aspect of the present invention, the pockets in the at least one external thread on the container finish are formed on an undersurface of the external thread and do not extend axially through the thread, such that the upper surface of the external thread is continuous throughout the external thread. This feature helps prevent cross threading during application of the closure to the container finish. In accordance with a further feature of the invention, the at least one external thread on the container finish and the at least one internal thread on the closure skirt may be of elongated dimension as compared with industry standards, and thread abutment stops are formed on the ends of the threads to prevent over-tightening of the closure and potential damage to the spring element. The elongated external thread on the container finish, particularly in combination with the pockets that do not extend axially through the external thread, permits the container to be used with a conventional non-child-resistant closure if desired, for example, by elderly persons. In dual lead packages, each thread on the closure may extend over an arc of 190° for example, and each thread on the finish may extend over an arc of 180°. In a single lead package with the thread stop at the bottom of the thread on the container finish, the closure thread may extend over an arc of 450° and the finish thread may extend over an arc of 455°. In single lead packages with the thread stop at the top of the closure thread, the closure thread may extend over an arc of 370° and the finish thread may extend over an arc of 360°.
A closure in accordance with a further aspect of the present invention is of integrally molded plastic construction. The closure has a base wall, a peripheral skirt with at least one internal thread and lugs on an upper surface of the thread, and a spring element on the base wall for engagement with a container finish to bias the lugs into opposing thread pockets on the container finish. The lugs have an angulated surface sloping toward an end of the thread remote from the base wall and a circumferentially facing radially extending abutment surface on an end of the lugs facing the opposing end of the thread. The spring element preferably comprises a circumferentially continuous conical lip that extends radially and axially inwardly from the base wall adjacent to the skirt. The lip tapers in thickness from the base wall to the free end of the lip to promote differential flexing of the lip upon engagement with a container finish or with a liner in opposed engagement with the container finish. The free end of the lip is rounded to permit sliding of the lip along the surface of a liner without binding or tearing. A container in accordance with yet another aspect of the invention includes an integrally molded plastic body having a finish with at least one external thread and pockets on an undersurface of the thread that do not extend axially through the thread, such that the upper surface of the thread is continuous throughout the thread. The pockets in the external thread have a circumferentially extending axially angulated cam surface and a radially extending abutment surface opposed to the cam surface.